Apparatus for centrifugal casting



Dec. 20, 1955 L. SAIVES 2,727,288

APPARATUS FOR CENTRIFUGAL. CASTING Filed May 8, 1955 United States Patent 2,727,288 APPARATUS FOR CENTRIFUGAL CASTING Lon Saives, Billancourt, France, assignor to Regie Nationale des Usines Renault, Billancourt, France Application May 8, 1953, Serial No. 353,759 Claims priority, application France June 13, 1952 2 Claims. (Cl. 22-65) This invention relates to an improved apparatus for centrifugal casting. This improvement can be applied to any centrifugal casting apparatus and makes it possible to cast, in split metal chill-moulds, parts which do not have a continuous flash running longitudinally, such as detachable engine liners or other cylinders for various purposes.

In centrifugal casting, as normally practised, a sand mould or a metal chill mould is used.

With a sand mould, the first step is to introduce into the centrifugal cylinder the mould, made of sand and having a core, and the inside of which represents the outside of the part to be made. This mould is kept in position by a fixed end-plate situated at the bottom of the rotating cylinder and by a detachable end-plate applied against the same mould, during rotation, by the action of the centrifugal force on a system of weights and levers. On removal, the whole thing is withdrawn and the sand mould is broken. It is therefore necessary to make one mould for each part.

Centrifugal chill casting requires, under present conditions, that the cast part should have a continuous longitudinal flash down the outside. As a result it is often necessary to provide castings having large machining allowances, resulting in high costs of machining.

Attempts have been made to combine the advantages of both methods of centrifugal casting by the possibility of making parts without flashes as in sand moulding, and the use of very long-lasting moulds as in chill-casting, using split chill moulds. But the halves of the chill mould, once assembled, must be able to be introduced into the centrifugal cylinder with a certain amount of play, in order to permit free expansion, and must remain firmly united in spite of the forces applied during the casting.

The object of the invention is to maintain the halves of the chills assembled by means of a system of centrifugal weights and levers acting on the external lateral surface of the split chills.

The accompanying drawings illustrate, by way of example, an apparatus intended for the casting in pairs of engine liners. But it is obvious that this embodiment can be applied to the casting of any revolving objects having a generatrix of any kind.

Figure 1 shows, in longitudinal section, the apparatus complete with its chill-moulds.

Figure 2 is a plan view of the centrifugal cylinder, and

Figure 3 is a section along AB in Figure l.

The apparatus consists of a cylinder 1 made of steel and carrying two circular flanges 2 running on the wheels of the driving device (not illustrated).

Inside the cylinder 1 are located a ring of sand 3 arranged to rest against an end-plate 4 and a stopwasher 5, two halves 6 and 7 of the chill mould, the face-piece 8 made of sand, and the cover 9. During rotation, the assembly is held longitudinally by the action of the centrifugal weights as reinforced counterweights 10, the tails of which act on the cover 9. This arrangement is already 2,727,288 Patented Dec. 20,

known. The rings of sand 3 and 8 are primarily intended to prevent the ends of the castings from cooling too rapidly. The halves 6 and 7 of the chill mould are arranged in the cylinder 1 with a considerable radial play permitting the relative expansion of the parts 1, 6 and 7.

Figure 1 shows two sets of split chill moulds 6, 7 and 6, 7 in the cylinder 1.

The cylinder 1 is pierced by four apertures 11, arranged in pairs diametrically opposite each other. Four centrifugal weights 12 are articulated about axes 13 entering a yoke welded to the cylinder 1. One end of the centrifugal weights carries a roller 14 which can rest on the halves of the chill moulds 6 and 7 through the apertures 11. The weights are designed in such a manner that the moment of the weight of the part carrying the roller in relation to the axis 13 is much less than the moment of the weight of the opposite part.

The operation of the apparatus is as follows:

The cylinder 1 and flanges 2, together with the four weights 12, the end-plate 4 and the stopwasher 5 having been mounted on the wheels of the driving carriage, the ring of sand 3, the two halves 6 and 7 of the chill'mould and the face-piece 8 made of sand are introduced successively into the cylinder 1, and it is closed by means of the cover 9. The plane of the joint of the two halves of the chill mould 6 and 7 is arranged perpendicularly to the symmetrical plane of the weights 12. Experience has shown that the device functions perfectly without any other centering of the chill moulds 6 and 7 being necessary.

When it is set in rotation, the action of centrifugal forces on the weights 12 causes the latter to pivot about the axes 13, and the rollers 14 tend to move towards the axis of the cylinder 1 and to keep the halves 6 and 7 of the chill moulds against one another, while permitting the expansion and the longitudinal positioning thereof. The masses of the weights 12 must be carefully calculated, primarily to counterbalance the disruptive force of the ralves 6 and 7 of the chill moulds due to the centrifugal force acting both on the chill moulds and on the metal being cast inside. The chill moulds are kept in position longitudinally by the action of the cover 9 and of the weights of the reinforced counterweight l0 acting on the cover 9 in a manner similar to that in which the weights 12 act on the halves 6 and 7 of the chill moulds.

I claim:

1. A centrifugal casting apparatus for use with split cylindrical chill moulds in the casting of metals which comprises, in combination, a cylindrical casing adapted to receive the chill moulds interiorly thereof, means for closing the ends of said cylindrical casing, radially-extending annular flanges provided on the external surface of said cylindrical casing adjacent the ends thereof, said cylindrical casing being provided with a plurality of circumferentially spaced-apart apertures positioned axially inwardly of said flanges, a lever radially aligned with each of said apertures and pivoted on a fulcrum radially outwardly of said casing adjacent said apertures, said flanges being provided with openings aligned with said levers and each lever having an outer arm extending through the adjacent opening and carrying a weight at its free end, and each lever having an inner arm extending over the adjacent aperture, said inner arm carrying an axle, and at least one roller mounted on said axle, said roller being dimensioned to pass through the adjacent aperture into contact with the peripheral surface of the chill mould contained in said cylindrical casing whereby upon rotation of said cylindrical casing during centrifu gal casting the Weights at the ends of the outer arms of the levers are urged outwardly under the influence of centrifugal force and cause said rollers to engage the chill moulds with a rolling resilient contact to press the halves of the chill moulds into operative engagement while permitting free expansion and longitudinal displacement of said chill moulds.

2. A centrifugal casting apparatus for use with split cylindrical chill moulds in the casting'of metals which comprises, in combination, a cylindrical casing adapted to receive the chill moulds-interiorly thereof, means for closing the ends of said cylindrical casing, the means closing one end of said cylindrical casing comprising a cover and centrifugal weights pivotally mounted on said casing and having arms bearing against said cover, radially-extending annular flanges provided on the external surface of said cylindrical casing adjacent the ends thereof, said cylindrical casing being provided with a plurality of circumferentially spaced-apart apertures positioned axially inwardly of said flanges, a lever radially aligned with roller being dimensioned to pass through the adjacent aperture into contact with the peripheral surface of the chill mould contained in said cylindrical casing whereby upon rotation of said cylindrical casing during centrifugal casting the weights at the ends of the outer arms of the levers are urged outwardly under the influence of centrifugal force and cause said rollers to engage the chill moulds with a rolling resilient contact to press the halves of the chill moulds into operative engagement while permitting free expansion and longitudinal displacement of said chill moulds.

References Cited in the file of this patent UNITED STATES PATENTS 

